As Facebook founder Mark Zuckerberg appears today before a congressional committee, the social media magnate is bound to attract pervasive media coverage. But the spotlight is on the wrong party.

The real culprit in the Facebook/Cambridge Analytica scandal is Robert Mercer, the major backer of Cambridge Analytica, who has frankly acknowledged his willingness to use his hedge-fund fortune to manipulate American politics. Facebook certainly had a role in the scandal, but the driving force was Mercer, not Zuckerberg.

Republicans are eager to question Zuckerberg in part because of a long-running campaign by Fox News to discredit not just Facebook but all of Silicon Valley. The Fox script is a familiar one: the “cool kids” in California look down on us, and they support all those liberals in the Democratic Party. Therefore, they are fair game — they do not enjoy the default support that Americans who run businesses otherwise enjoy from Fox and the Republican Party.

By the same logic, there is one key player in the Facebook data scandal who will almost certainly NOT be summoned before Congress: Mercer. That’s because congressional Republicans are terrified of Mercer. He is a billionaire who spends tens of millions of dollars a year supporting conservative candidates for office. He is a principal backer of Cambridge Analytica, the shadowy political consultants who helped elect Donald Trump in 2016.

If you want to hear Mercer testifying in Congress, you’ll have to wait for a Democratic majority to get back in power and resume governing.